<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
    <title>centroid</title>
    <link rel="stylesheet" type="text/css" href="csound.css" />
    <meta name="generator" content="DocBook XSL Stylesheets V1.78.1" />
    <link rel="home" href="index.html" title="The Canonical Csound Reference Manual" />
    <link rel="up" href="OpcodesTop.html" title="Orchestra Opcodes and Operators" />
    <link rel="prev" href="cent.html" title="cent" />
    <link rel="next" href="cggoto.html" title="cggoto" />
  </head>
  <body>
    <div class="navheader">
      <table width="100%" summary="Navigation header">
        <tr>
          <th colspan="3" align="center">centroid</th>
        </tr>
        <tr>
          <td width="20%" align="left"><a accesskey="p" href="cent.html">Prev</a> </td>
          <th width="60%" align="center">Orchestra Opcodes and Operators</th>
          <td width="20%" align="right"> <a accesskey="n" href="cggoto.html">Next</a></td>
        </tr>
      </table>
      <hr />
    </div>
    <div class="refentry">
      <a id="centroid"></a>
      <div class="titlepage"></div>
      <a id="IndexCentroid" class="indexterm"></a>
      <div class="refnamediv">
        <h2>
          <span class="refentrytitle">centroid</span>
        </h2>
        <p>centroid — 
      Calculate the spectral centroid of a signal.
    </p>
      </div>
      <div class="refsect1">
        <a id="idp93235296"></a>
        <h2>Description</h2>
        <p>
      Calculate the spectral centroid of an audio signal on a given trigger.
    </p>
      </div>
      <div class="refsect1">
        <a id="idp93236576"></a>
        <h2>Syntax</h2>
        <pre class="synopsis">kcent <span class="command"><strong>centroid</strong></span> asig, ktrig, ifftsize</pre>
      </div>
      <div class="refsect1"><a id="idp93300288"></a><h2>Initialization</h2><span class="emphasis"><em>ifftsize</em></span>  -- fftsize. Non pow-of-two values are converted to the next pow-of-two not smaller than ifftsize. 
  </div>
      <div class="refsect1">
        <a id="idp93301616"></a>
        <h2>Performance</h2>
        <p>
      <span class="emphasis"><em>kcent</em></span> -- the spectral centroid in Hz
    </p>
        <p>
      <span class="emphasis"><em>asig</em></span> -- an input audio signal
    </p>
        <p>
      <span class="emphasis"><em>ktrig</em></span> -- 1 to calculate a new centroid, 0 to skip the process (and output previous value).
    </p>
      </div>
      <div class="refsect1">
        <a id="idp93305024"></a>
        <h2>Examples</h2>
        <p>
      Here is an example of the centroid opcode. It uses the file <a class="ulink" href="examples/centroid.csd" target="_top"><em class="citetitle">centroid.csd</em></a>.
      </p>
        <div class="example">
          <a id="idp93306880"></a>
          <p class="title">
            <strong>Example 106. Example of the centroid opcode.</strong>
          </p>
          <div class="example-contents">
            <p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p>
            <pre class="programlisting">
<span class="csdtag">&lt;CsoundSynthesizer&gt;</span>
<span class="csdtag">&lt;CsOptions&gt;</span>
<span class="comment">; Select audio/midi flags here according to platform</span>
-odac     <span class="comment">;;;realtime audio out</span>
<span class="comment">;-iadc    ;;;uncomment -iadc if realtime audio input is needed too</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o centroid.wav -W ;;; for file output any platform</span>
<span class="csdtag">&lt;/CsOptions&gt;</span>
<span class="csdtag">&lt;CsInstruments&gt;</span>

<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">ksmps</span> <span class="op">=</span> 32
<span class="ohdr">nchnls</span> <span class="op">=</span> 2
<span class="ohdr">0dbfs</span>  <span class="op">=</span> 1

giSine <span class="ohdr">ftgen</span> 0, 0, 16384, 10, 1

<span class="oblock">instr</span> 1

ktrig <span class="opc">init</span> 1				<span class="comment">;calculate centroid</span>
a1   <span class="opc">oscil3</span> 0.5, p4, giSine		<span class="comment">;of the sine wave</span>
k1   <span class="opc">centroid</span> a1, ktrig, 16384
asig <span class="opc">oscil3</span> 0.5, k1, giSine
     <span class="opc">printk2</span> k1				<span class="comment">;print &amp; compare:</span>
     <span class="opc">outs</span> a1, asig			<span class="comment">;left = original, right = centroid signal</span>

<span class="oblock">endin</span>
<span class="csdtag">&lt;/CsInstruments&gt;</span>
<span class="csdtag">&lt;CsScore&gt;</span>

<span class="stamnt">i</span>1 0 2 20
<span class="stamnt">i</span>1 + 2 200
<span class="stamnt">i</span>1 + 2 2000
<span class="stamnt">e</span>     

<span class="csdtag">&lt;/CsScore&gt;</span>
<span class="csdtag">&lt;/CsoundSynthesizer&gt;</span>
</pre>
          </div>
        </div>
        <p><br class="example-break" />
    </p>
      </div>
      <div class="refsect1">
        <a id="idp93311168"></a>
        <h2>See Also</h2>
        <p>
      <a class="link" href="pvscent.html" title="pvscent"><em class="citetitle">pvscent</em></a>
    </p>
      </div>
      <div class="refsect1">
        <a id="idp93313216"></a>
        <h2>Credits</h2>
        <p>
      </p>
        <table border="0" summary="Simple list" class="simplelist">
          <tr>
            <td>Author: V Lazzarini;</td>
          </tr>
          <tr>
            <td>August 2012</td>
          </tr>
        </table>
        <p>
    </p>
      </div>
    </div>
    <div class="navfooter">
      <hr />
      <table width="100%" summary="Navigation footer">
        <tr>
          <td width="40%" align="left"><a accesskey="p" href="cent.html">Prev</a> </td>
          <td width="20%" align="center">
            <a accesskey="u" href="OpcodesTop.html">Up</a>
          </td>
          <td width="40%" align="right"> <a accesskey="n" href="cggoto.html">Next</a></td>
        </tr>
        <tr>
          <td width="40%" align="left" valign="top">cent </td>
          <td width="20%" align="center">
            <a accesskey="h" href="index.html">Home</a>
          </td>
          <td width="40%" align="right" valign="top"> cggoto</td>
        </tr>
      </table>
    </div>
  </body>
</html>
